One experiment with rats explored whether an extinction-cue prevents the recovery of extinguished lever-pressing responses. Initially, rats were trained to perform one instrumental response (R1) for food in Context A, and a different instrumental response (R2) in Context B. Then, responses were extinguished each in the alternate context (R1 in…

Behavioral data suggest that distinguishable orientations may be necessary for place learning even when distal cues define different start points in the room and a unique goal location. We examined whether changes in orientation are also important in place learning and navigation in a water T-maze. In Experiment 1, rats were trained to locate a…

To test the hypothesis that pigeons will only code the more salient sample when samples differ markedly in salience, pigeons were trained with samples consisting of a 2-s presentation of food (highly salient sample) and an 8-s presentation of keylight (less salient sample). During retention testing, pigeons tended to respond at longer delays as if…

Appetitive contextual excitation supported by intertrial unconditioned stimuli was more easily overcome by timed conditioned responding in rats using quiet (Experiment 1) rather than noisy (Experiment 2) food pellet deliveries. Head-entry responding in acquisition peaked above the contextual baseline when pellet delivery occurred 10, 30, 60, or 90…

Previous research has shown that rats increase their rate of responding for 1% sucrose reinforcement in the first half of the session if food-pellet, rather than 1% sucrose, reinforcement will be available in the second half (i.e., positive induction). Four experiments investigated whether this induction effect would be changed by altering the…

Research has demonstrated that rats' rates of operant behavior maintained by 1% sucrose reinforcement in the first half of an experimental session are heightened when food-pellet reinforcers, rather than 1% sucrose, will be available in the second half. Experiment 1 showed that rats that had been displaying this positive induction effect acquired…

In three experiments the location of pigeons was monitored during 20-second illuminations of a right or left key presented in various temporal relationships with food delivery. In general, subjects approached a signal positively correlated with food and withdrew from a signal negatively correlated with food. (Editor)

The main finding of these four experiments was that the strong conditioning produced by a brief exposure to a truly random control weakened with prolonged exposure. (Author/RK)

Whether a stimulus compound is separable or integral has predictable consequences for several human information processing tasks. The purpose of these experiments was to explore the implications of this distinction for research in animal learning and the development of learning theory. (Author/RK)

Assesses the validity of physiological versus learning interpretations of illness-preexposure effects. (Author/RK)

There has been considerable interest lately in cases where instrumental conditionability appears to depend on the reinforcer used. Here the effects of Pavlovian conditioned stimuli (CSs)on golden hamster behaviors was observed. The intent was to see whether previously reported differences among the behaviors produced by food reinforcement and…

Recent data indicate that the form of the conditioned response (CR) may often be substantially influenced by the characteristics of the conditioned stimulus (CS) as well as by those of the unconditioned stimulus (US). Here five experiments examine the influence of CS characteristics on the form of the Pavlovian CR anticipatory to a food US in…

These experiments attempt to optimize the possibility of demonstrating blocking in a taste-aversion paradigm and to elucidate the conditions under which this interference occurs. (Author/RK)

To complement investigations of the direct effects of lithium toxicosis on consummatory behavior, these experiments were designed to determine the aftereffects on drinking of exposure to a conditioned stimulus previously paired with lithium. (Author/RK)

In four different experiments, brief illumination of a localized visual stimulus was followed by grain presentation unless the pigeon approached the light. Results indicate that although response-reinforcer relations do play a role, stimulus-reinforcer contingencies are the dominant factor in establishing and maintaining approaches to the…